A novel cloud-point extraction (CPE) was successfully used in preconcentration of biphenol A (BPA) from aqueous solutions. Majority of BPA is extracted into the surfactant-rich phase. The parameters affecting the ...A novel cloud-point extraction (CPE) was successfully used in preconcentration of biphenol A (BPA) from aqueous solutions. Majority of BPA is extracted into the surfactant-rich phase. The parameters affecting the CPE such as concentration of surfactant and electrolyte, equilibration temperature and time and pH of sample solution were investigated. The samples were analyzed by high-performance liquid chromatography with ultraviolet detection. Under the optimized conditions, preconcentration of 10 mL sample gives a preconcentration factor of 11. The limit of detection (LOD) and limit of quantification (LOQ) are 0.1 μg/L and 0.33 μg/L, respectively. The linear range of the proposed method is 0.2-20 μg/L with correlation coefficients greater than 0.998 7 and the spiking recove6es are 97.96%-100.42%. The interference factor was tested and the extraction mechanism was also investigated. Thus, the developed CPE has proven to be an efficient, green, rapid and inexpensive approach for extraction and preconcentration of BPA from water samples.展开更多
The purpose of this procedure was to optimize and improve a method that used for the determination of arsenic (Ⅲ) and arsenic (Ⅴ) in biological and environmental samples. The method is based on hydride generatio...The purpose of this procedure was to optimize and improve a method that used for the determination of arsenic (Ⅲ) and arsenic (Ⅴ) in biological and environmental samples. The method is based on hydride generation and atomic absorption spectrometry. For both As (Ⅲ) and As (Ⅴ) the parameters such as NaBH4, HCI concentration, and pH were optimized. Absorption signal of As (Ⅴ) was approximately 17% of As (Ⅲ) signal. Therefore, for estimation of As (Ⅲ) and As (Ⅴ) concentrations in various samples the difference between the absorbance obtained for arsenic, without and with previous treatment of samples with potassium iodide (KI), can be applied. The calibration graphs were linear (r〉0.99), and the detection limits of the method based on three times the standard deviation of the blank were 0.14 and 0.64 μL^-1 for As (Ⅲ) and As (Ⅴ), respectively. The relative standard deviation (R.S.D.) of measurements was less than 10%. As a means of checking performance method, water samples were spiked with known concentrations of both As (Ⅲ) and As (Ⅴ), and recovery above 94% was obtained. The proposed method was applied successfully to determine inorganic As (Ⅲ) and As (Ⅴ) in various environmental and total As in biological samples.展开更多
Rare-earth dements (REE) in limestones were measured by ICP-MS from the Yangdi section across the Frasnian-Famennian (F-F) transition in Guilin, Guangxi of South China. The average EREE contents of measured sample...Rare-earth dements (REE) in limestones were measured by ICP-MS from the Yangdi section across the Frasnian-Famennian (F-F) transition in Guilin, Guangxi of South China. The average EREE contents of measured samples are 33.32 ppm. The average LREE/HREE ratio is 6.35. Data show LREE-enriched REE distribution pattern in the Yangdi section. Most of samples are characterized by positive Eu anomaly with average of 1.13, and there are two maxima of Eu anomaly just below the F-F boundary. Almost all analytical samples show obvious tetrad effects. Remarkable M-shaped tetrad effects are observed in these samples with positive Eu anomaly. The characters of REE and some relative elements (Fe, Mn, Al, etc.) indicate that hydro- thermal activities occurred and resulted in seawater acidification in Upper and Lower Kellwasser horizons of the Late Devonian. The changes of marine environment caused by hydrothermal activities, such as seawater acidification, heavy metal pollution, and eutrophication, would destroy the neritic ecosystem and finally result in the F-F mass extinction.展开更多
基金Project(20956001) supported by the National Natural Science Foundation of ChinaProject(CX2011B083) supported by Hunan Provincial Innovation Foundation for Postgraduate, ChinaProject(K1104026-11) supported by Project of Changsha Science and Technology Bureau, China
文摘A novel cloud-point extraction (CPE) was successfully used in preconcentration of biphenol A (BPA) from aqueous solutions. Majority of BPA is extracted into the surfactant-rich phase. The parameters affecting the CPE such as concentration of surfactant and electrolyte, equilibration temperature and time and pH of sample solution were investigated. The samples were analyzed by high-performance liquid chromatography with ultraviolet detection. Under the optimized conditions, preconcentration of 10 mL sample gives a preconcentration factor of 11. The limit of detection (LOD) and limit of quantification (LOQ) are 0.1 μg/L and 0.33 μg/L, respectively. The linear range of the proposed method is 0.2-20 μg/L with correlation coefficients greater than 0.998 7 and the spiking recove6es are 97.96%-100.42%. The interference factor was tested and the extraction mechanism was also investigated. Thus, the developed CPE has proven to be an efficient, green, rapid and inexpensive approach for extraction and preconcentration of BPA from water samples.
文摘The purpose of this procedure was to optimize and improve a method that used for the determination of arsenic (Ⅲ) and arsenic (Ⅴ) in biological and environmental samples. The method is based on hydride generation and atomic absorption spectrometry. For both As (Ⅲ) and As (Ⅴ) the parameters such as NaBH4, HCI concentration, and pH were optimized. Absorption signal of As (Ⅴ) was approximately 17% of As (Ⅲ) signal. Therefore, for estimation of As (Ⅲ) and As (Ⅴ) concentrations in various samples the difference between the absorbance obtained for arsenic, without and with previous treatment of samples with potassium iodide (KI), can be applied. The calibration graphs were linear (r〉0.99), and the detection limits of the method based on three times the standard deviation of the blank were 0.14 and 0.64 μL^-1 for As (Ⅲ) and As (Ⅴ), respectively. The relative standard deviation (R.S.D.) of measurements was less than 10%. As a means of checking performance method, water samples were spiked with known concentrations of both As (Ⅲ) and As (Ⅴ), and recovery above 94% was obtained. The proposed method was applied successfully to determine inorganic As (Ⅲ) and As (Ⅴ) in various environmental and total As in biological samples.
基金supported by Natural Science Foundation of China(Grant Nos.40730209,40802005,40872001,40921062)the"111" Project(Grant No.B08030)the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources
文摘Rare-earth dements (REE) in limestones were measured by ICP-MS from the Yangdi section across the Frasnian-Famennian (F-F) transition in Guilin, Guangxi of South China. The average EREE contents of measured samples are 33.32 ppm. The average LREE/HREE ratio is 6.35. Data show LREE-enriched REE distribution pattern in the Yangdi section. Most of samples are characterized by positive Eu anomaly with average of 1.13, and there are two maxima of Eu anomaly just below the F-F boundary. Almost all analytical samples show obvious tetrad effects. Remarkable M-shaped tetrad effects are observed in these samples with positive Eu anomaly. The characters of REE and some relative elements (Fe, Mn, Al, etc.) indicate that hydro- thermal activities occurred and resulted in seawater acidification in Upper and Lower Kellwasser horizons of the Late Devonian. The changes of marine environment caused by hydrothermal activities, such as seawater acidification, heavy metal pollution, and eutrophication, would destroy the neritic ecosystem and finally result in the F-F mass extinction.